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<div id="layout">
  <div id="layout-content"><div id="mongodb-driver-cursor.isdead" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">MongoDB\Driver\Cursor::isDead</h1>
  <p class="verinfo">(mongodb &gt;=1.0.0)</p><p class="refpurpose"><span class="refname">MongoDB\Driver\Cursor::isDead</span> &mdash; <span class="dc-title">Checks if the cursor is exhausted or may have additional results</span></p>

 </div>

 <div class="refsect1 description" id="refsect1-mongodb-driver-cursor.isdead-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="modifier">final</span> <span class="modifier">public</span> <span class="methodname"><strong>MongoDB\Driver\Cursor::isDead</strong></span>(): <span class="type">bool</span></div>

  <p class="para rdfs-comment">
   Checks whether there are definitely no additional results available on the
   cursor. This method is similar to the
   <a href="https://www.mongodb.com/docs/manual/reference/method/cursor.isExhausted/" class="link external">&raquo;&nbsp;cursor.isExhausted()</a>
   method in the MongoDB shell and is primarily useful when iterating
   <a href="https://www.mongodb.com/docs/manual/core/tailable-cursors/" class="link external">&raquo;&nbsp;tailable cursors</a>.
  </p>
  <p class="para">
   A cursor has no additional results and is considered &quot;dead&quot; when one of the
   following is true:
   <ul class="simplelist">
    <li class="member">
     The current batch has been fully iterated <em class="emphasis">and</em> the
     cursor ID is zero (i.e. a 
     <a href="https://www.mongodb.com/docs/manual/reference/command/getMore/" class="link external">&raquo;&nbsp;getMore</a>
     cannot be issued).
    </li>
    <li class="member">An error was encountered while iterating the cursor.</li>
    <li class="member">The cursor reached its configured limit.</li>
   </ul>
  </p>
  <p class="para">
   By design, it is not possible to always determine whether a cursor has
   additional results. The cases where a cursor <em class="emphasis">may</em> have
   more data available is as follows:
   <ul class="simplelist">
    <li class="member">
     There are additional documents in the current batch, which are buffered on
     the client side. Iterating will fetch a document from the local buffer.
    </li>
    <li class="member">
     There are no additional documents in the current batch (i.e. local buffer),
     but the cursor ID is non-zero. Iterating will request more documents from
     the server via a
     <a href="https://www.mongodb.com/docs/manual/reference/command/getMore/" class="link external">&raquo;&nbsp;getMore</a>
     operation, which may or may not return additional results and/or indicate
     that the cursor has been closed on the server by returning zero for its ID.
    </li>
   </ul>
  </p>
 </div>


 <div class="refsect1 parameters" id="refsect1-mongodb-driver-cursor.isdead-parameters">
  <h3 class="title">参数</h3>
  <p class="para">此函数没有参数。</p>
 </div>


 <div class="refsect1 returnvalues" id="refsect1-mongodb-driver-cursor.isdead-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   Returns <strong><code>true</code></strong> if there are definitely no additional results available on the
   cursor, and <strong><code>false</code></strong> otherwise.
  </p>
 </div>


 <div class="refsect1 errors" id="refsect1-mongodb-driver-cursor.isdead-errors">
  <h3 class="title">错误／异常</h3>
  <ul class="simplelist">
   <li class="member">Throws <span class="classname"><a href="class.mongodb-driver-exception-invalidargumentexception.html" class="classname">MongoDB\Driver\Exception\InvalidArgumentException</a></span> on argument parsing errors.</li>
  </ul>
 </div>



 <div class="refsect1 examples" id="refsect1-mongodb-driver-cursor.isdead-examples">
  <h3 class="title">范例</h3>
  <div class="example" id="example-1341">
   <p><strong>示例 #1 <span class="function"><strong>MongoDB\Driver\Cursor::isDead()</strong></span> example</strong></p>
   <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /><br />$manager&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">MongoDB</span><span style="color: #007700">\</span><span style="color: #0000BB">Driver</span><span style="color: #007700">\</span><span style="color: #0000BB">Manager</span><span style="color: #007700">(</span><span style="color: #DD0000">"mongodb://localhost:27017"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$query&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">MongoDB</span><span style="color: #007700">\</span><span style="color: #0000BB">Driver</span><span style="color: #007700">\</span><span style="color: #0000BB">Query</span><span style="color: #007700">([]);<br /><br /></span><span style="color: #0000BB">$bulk&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">MongoDB</span><span style="color: #007700">\</span><span style="color: #0000BB">Driver</span><span style="color: #007700">\</span><span style="color: #0000BB">BulkWrite</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$bulk</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">insert</span><span style="color: #007700">([</span><span style="color: #DD0000">'x'&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #0000BB">1</span><span style="color: #007700">]);<br /></span><span style="color: #0000BB">$bulk</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">insert</span><span style="color: #007700">([</span><span style="color: #DD0000">'x'&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #0000BB">2</span><span style="color: #007700">]);<br /></span><span style="color: #0000BB">$bulk</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">insert</span><span style="color: #007700">([</span><span style="color: #DD0000">'x'&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #0000BB">3</span><span style="color: #007700">]);<br /></span><span style="color: #0000BB">$manager</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">executeBulkWrite</span><span style="color: #007700">(</span><span style="color: #DD0000">'db.collection'</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$bulk</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$cursor&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$manager</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">executeQuery</span><span style="color: #007700">(</span><span style="color: #DD0000">'db.collection'</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$query</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$iterator&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">IteratorIterator</span><span style="color: #007700">(</span><span style="color: #0000BB">$cursor</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$iterator</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">rewind</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$cursor</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">isDead</span><span style="color: #007700">());<br /><br /></span><span style="color: #0000BB">$iterator</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">next</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$cursor</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">isDead</span><span style="color: #007700">());<br /><br /></span><span style="color: #0000BB">$iterator</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">next</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$cursor</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">isDead</span><span style="color: #007700">());<br /><br /></span><span style="color: #0000BB">$iterator</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">next</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$cursor</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">isDead</span><span style="color: #007700">());<br /><br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
   </div>

   <div class="example-contents"><p>以上例程会输出：</p></div>
   <div class="example-contents screen">
<div class="cdata"><pre>
bool(false)
bool(false)
bool(false)
bool(true)
</pre></div>
   </div>
  </div>
 </div>


 <div class="refsect1 seealso" id="refsect1-mongodb-driver-cursor.isdead-seealso">
  <h3 class="title">参见</h3>
  <ul class="simplelist">
   <li class="member"><a href="https://www.mongodb.com/docs/manual/core/tailable-cursors/" class="link external">&raquo;&nbsp;Tailable Cursors</a> in the MongoDB manual</li>
   <li class="member"><a href="https://www.mongodb.com/docs/manual/reference/method/cursor.isExhausted/" class="link external">&raquo;&nbsp;cursor.isExhausted()</a> in the MongoDB manual</li>
  </ul>
 </div>


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